Issue 123

The XML Schema primer http://www.w3.org/TR/xmlschema-0/
has an example of how to define an element that can contain mixed content.
This is exactly the same as Mike Edwards' suggestion except that the 
sequence is
typed as xsd:string rather than xsd:any.

I suspect Mike used ##any to allow simple data values but that not helpful.
because you don't know what the simple types are and cannot validate them.
Thus 5.0 will look like a string in any case.  The simple types will be 
validated
in the specific context where they are used.

Thus, unless Mike has other reasons to prefer ##any, xsd:string seems 
simpler and equally effective.
-- 
All the best, Ashok